System and method to manage utility meter communications

ABSTRACT

A method for managing communications within a network comprising utility meters, each associated and connected to at least one utility management center through at least one intermediate data concentrator. A message is sent by a utility meter to the destination data concentrator. This message includes metering data measurement reported by said utility meter, its utility meter identifier, the destination data concentrator identifier and the management center identifier. Then, on the basis of several metering data measurements, a metering counter differential consumption value is calculated by difference of two metering counter consumption indexes measured by the utility meter within a time period interval. Then, a report containing at least the metering counter differential consumption value is sent from the destination data concentrator towards the utility management center to which said utility meter is associated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.14/342,270, filed Feb. 28, 2014, which is a National Stage ofInternational Application No. PCT/EP2012/066803, filed Aug. 30, 2012,which claims priority to European Application No. EP 11179337.8, filedAug. 30, 2011 and to U.S. Provisional Application No. 61/528,822, filedAug. 30, 2011. The entire contents of each of which are incorporatedherein by reference.

TECHNICAL FIELD

This invention concerns the field of utility meters that are monitoredand managed from at least one utility management center through at leastone intermediate data concentrator in a communication network.

BACKGROUND ART

The on-going deregulation in worldwide energy distribution markets isdriving the need for smart utility distribution grids and smart meters,enabling both utility providers and consumers to monitor the detailedconsumption of an end user at any time through open communicationnetworks. The energy market is particularly concerned as of today butrelated issues are also relevant to other utility markets such as wateror gas.

While a number of legacy meters already implement some point-to-pointAutomated Metering Reading (AMR) protocols using for instance standardoptical or modem interfaces, they are not able to interact with eitherthe end user home area network devices or the remote utility monitoringfacilities using wireless or power line communication networks. Theindustry answer to this regulatory requirement in the next decade willtherefore consist in swapping the legacy meters for so-called smartmeters.

Smart meters enable utility providers to monitor the detailedconsumption of an end user at any time through open communicationnetworks. The consumption measurement sampling granularity can then bemuch finer than in legacy systems where the meters were manuallycontrolled about once a year. It is also possible to support multipletariffs from different providers and adapt them much more frequently inaccordance with the finer measurement periods.

From the utility provider perspective, as there will be no more localmeasurement and physical control of the meter functionality byauthorized personnel, the smart metering architecture needs carefuldesign to ensure secure, tamper resistant and trusted data collectionand transmission from the smart meters to the provider utility servicesfacility. Various solutions can be defined based on state of the artcryptography protocols and a key management system under the control ofthe utility provider. Those solutions typically require the smart meterto generate its measurement reporting messages specifically for a givenutility provider. In a deregulated market where the smart meter is ableto negotiate its tariffs with multiple providers, this results inincreased bandwidth and processing needs as well as tamper resistantdesign complexity, manufacturing costs and maintenance costs for theutility meters.

The document US 2008/0068213 discloses automatic meter reading systemsfor receiving standard consumption messages fromencoder-receiver-transmitter devices located at the end user. To thisend, these devices communicate with reading systems that periodicallycollect reading of residential gas, electric or water meters by using RFcommunications. Each encoder-receiver-transmitter device is uniquelyidentifiable so that its information can be properly associated with thecorresponding customer account for billing purposes. Theencoder-receiver-transmitter devices operates in a low-power standbymode during a majority of the time and it is provided with a timer whichoperates to periodically wake up the device so that it enters into anactive operating mode.

The document U.S. Pat. No. 5,974,369 discloses an energy managementsystem, in particular a recording node for receiving energy-relatedconsumption meter data for calculating consumption amount andconsumption rate for a particular time interval and for storing suchinformation. Price data may be received at the recording node from anexternal source, e.g. over a network, such as a distributed network,which network may include the recording node. Pricing information mightbe updated any time a price change is implemented or projected. Serviceprovider can receive previously accumulated consumption values andassociated prices for past consumption intervals, for billing purposesover network. Data calculated by the recording node is available forreading by any authorized nodes on network or by other authorizedexternal devices.

However, while keeping in mind that reporting data refers simultaneouslyto millions of utility meters, none of these documents suggests meansfor optimizing as far as possible the management of exchanged data inorder to save bandwidth and computing resources. Besides, thesedocuments merely suggest exchanging communications through a knownnetwork without taking care to prevent hacking and tampering caused bycertain malicious persons.

From a security point of view, it is difficult to implement a powerfulsystem for exchanging data, metered by a huge quantity of utilitymeters, which is fully tamper-proof against hackers. For instance, it isnot reliable to implement a single cryptography system for reporting allutility meters given that such a system would require, for all thesemeters, a shared key that would be difficult to keep secret. As taughtby the prior art, it is much easier to implement a security system byusing physical access controls in order to monitor sensitive devices,for instance by installing locked gates and video monitoring cameras.

There is therefore a need for a more flexible smart metering networktopology to optimize the smart metering operations, communications, andsecurity.

SUMMARY

A metering reporting communication method utilizes at least one dataconcentrator proxy located as intermediate device between the utilitymeter and the utility provider. More particularly, a method for managingutility meter communications within a network comprising a plurality ofutility meters, each associated and connected to at least one utilitymanagement center through at least one intermediate data concentrator,each utility meter being identified by a utility meter identifier andbeing adapted to produce and send utility meter messages to adestination data concentrator identified by a data concentratoridentifier, each destination data concentrator being adapted to produceand send reports to said management center, the latter being identifiedby a management center identifier, the method comprising the steps of:

sending a utility meter message from a utility meter to the destinationdata concentrator, this utility meter message including: a metering datameasurement reported by said utility meter, the utility meteridentifier, the destination data concentrator identifier and themanagement center identifier;

determining, on the basis of several metering data measurements, ametering counter differential consumption value calculated by differenceof two metering counter consumption indexes measured by said utilitymeter within a certain time period interval;

sending, from the destination data concentrator towards the utilitymanagement center to which said utility meter is associated, a reportcontaining at least the metering counter differential consumption value.

The present invention also refers to a system able to implement theabove mentioned method.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood thanks to the attachedfigures in which:

FIG. 1 shows a schematic illustration of a star-shaped networkcomprising end user utility meters, data concentrators and utilityprovider management centers.

FIG. 2 shows tariffs tables of utility providers.

DETAILED DESCRIPTION

The proposed solution comprises a data concentrator which is connectedboth to the smart meter and to a number of utility providers.

FIG. 1 illustrates one possible smart grid network topology, based on astar-shaped network of subset of end user utility meters U1, U2, U3,which are preferably directly connected to at least an intermediate dataconcentrator C2. This data concentrator being at its turn connected toat least one utility provider management center. The concentrator istypically co-located with the low-voltage utility distribution to aneighborhood and monitors up to several thousands of utility meters. Ina deregulated utility market, the data concentrator C2 can be furtherconnected to multiple utility providers P1, P2, P3 who are offeringcompeting utility delivery offerings to the end user (FIG. 1).

Each utility management center P1, P2, P3 implements various utilitymanagement processes such as data management billing, load managementand outage control, and queries and controls the data concentrators C1,C2, C3, C4 accordingly through the smart grid global communicationnetwork links Lpc.

Each data concentrator C1, C2, C3, C4 comprises functional components incharge with enforcing meter usage monitoring and reporting to theutility management center by means of secure communications with theindividual meters through the local communication network links Luc onthe one hand and with the utility providers management centers throughthe global smart grid network links Lcp on the other hand.

Each communication network link Lcp, Luc from FIG. 1 is built over autility metering communication physical network, such as, but notlimited to, a cable network, the power line wire, a wireless network, ora combination thereof, and employs a communication networking protocol,such as, but not limited to, Internet Protocol (IP) v4 or v6. On top ofthose networks, communication messaging for smart grids and smart metersis largely inspired by the telecommunication industry and subject toemerging standardization by international committees such as ANSI orIEC.

In a deregulated market, each end user can choose its preferred utilityprovider. For instance utility provider P3 is selected for utilitymeters U1 and U3 while utility provider P1 is chosen for utility meterU2. As utility offerings evolve towards a finer granularity and morefrequent renewal of the tariffs, the utility meters have to process themaccordingly and report their utility consumption at a higher rate thanbefore, for instance every 15 minutes. This overloads both the limitedmeter processing power and the communication network between the utilityproviders and the utility meters.

This problem is avoided by a distributed computing system in which thedata concentrator C establishes secure communications with each utilitymeter U, receives the regular utility consumption reports DTup_(u,c)from each utility meter U, and computes a consolidated report RTup_(u,p)for the utility provider P associated with said utility meter U. Theadvantage of this solution is that the utility meter only needs toestablish, encrypt and sign one DTup_(u,c) message for the dataconcentrator C to report its consumption without having to bear thedetailed tariff computation, which evolves over time, requires specifictechnical resources and needs frequent updates. The utility metermessage DTup_(u,c) typically comprises at least an information relatingone time and date DT and the metering counter consumption index CPTmeasured by the utility meter U at this time and date DT, or themetering counter differential consumption value ΔCPT measured betweenthe former transmitted time and date DTprev and the current time anddate DTcurr. In a simpler mode of implementation where the utility meterand the data concentrator communicate synchronously, i.e. on the basisof synchronized clocks where one clock is located within the utilitymeter and the other within the data concentrator, only the utility meterconsumption index is transmitted to the data concentrator which is incharge with measuring the corresponding date and time. However, itshould be noted that these two clocks do not need to have the same timebasis, for instance the clock located within the data concentrator couldbe a common clock, whereas the clock of the utility meter could bemerely a count-down or a means able to produce pulses. In a furtheralternative, the utility meter could transmit only its consumption indexto the data concentrator, only on request from the latter. For the sakeof clarity, it should be noted that the word “index” refers to a numberthat is counted by the utility meter. For instance, this number canrelate to a consumption quantity expressed in KW/h or in m³ or in anyother unit depending on the purpose for which the utility meter is used(i.e. whether it is used for metering electricity, water, gas, etc . . .).

In order to identify their source and their destination in an opencommunication network, the DTup_(u,c) message also includes the sourceutility meter identifier Uid, the destination data concentratoridentifier DCid, and the utility provider identifier Pid. The latteridentifiers may be an integral value uniquely associated with theequipment at manufacturing time, a network address identifier, or anycombination thereof.

In order to ensure the integrity of the utility meter messages, they canbe further signed so that the data concentrator authenticates that themetering report comes from a genuine utility meter source. In order toensure the confidentiality of the utility meter messages as desired (forinstance to ensure end user consumption data privacy), they can also beencrypted so that the utility meter data is only accessible by theauthorized data concentrator destination.

In terms of security design, most smart grid standards require theestablishment of a Public Key Infrastructure (PKI) where each node inthe network is associated with a pair of public and private asymmetriccryptography keys, for instance a RSA key pair, and a chain of publickey certificates signed by a trusted central authority, for instanceX.509 certificates. In a simple implementation corresponding to the gridtopology of FIG. 1, in order to report its metering data measurementDTup within a utility meter message DTUP_(u,c), the utility meter U1generates a random payload key Kp, encrypts it with the public keyKpubC2 of the data concentrator C2, and encrypts and signs the datameasurement DTup by means of Kp. It transmits (Kp)KpubC2 and (DTup)Kp inone or several messages to the data concentrator C2, which decrypts theKp value by means of its unique, secret private key KprivC2, and thenthe payload data DTup by means of the formerly decrypted Kp key. In amore optimized implementation, a Secure Authenticated Channel (SAC) canbe negotiated by the utility meter and the data concentrator toestablish a longer term shared session key Ks. This session key Ks canthen be used similarly to the former payload key Kp but repeatedly, fora certain period of time, to enforce communication message integrity andconfidentiality in the point-to-point transmission between the utilitymeter and the data concentrator. The available offerings from theutility providers are represented by tariffs tables which can be sent bythe utility providers P1-P3 to each data concentrator C1-C4 connected tothese providers. In order to disclose these tables in a secured manner,these tables are sent within secured utility provider messages. Such amessage can be secured by several manners. A first manner is to encryptthe message according to a symmetric or a private/public scheme. Asecond manner to secure this message can be obtained by signing thismessage in view to protect its content against any modification. Thiscan be done by the sender through a one-way function (e.g. a hashfunction) applied to the message to be sent in order to get a hash valuewhich is then encrypted by means of the private key of the sender. Thisencrypted hash value (corresponding to a signature) can be decrypted bythe recipient by using the public key of the sender. Besides, thispublic key can be also authenticated by a certificate from a certificateauthority. Another way to secure the message is to send a signed andencrypted message. Such a message provides a double protection giventhat it is protected, on the one hand against any easy reading by itsencryption layer, and on the other hand against any tampering of itscontent thanks to the signature and the certificate. Thus, theauthenticity and the integrity of the message can be advantageouslycombined to its encryption. Applying encryption and/or signingoperations can be performed with any message, e.g. with utility messagesor data concentrator messages. A tariff table, as represented in FIG. 2,provides a consumption unit invoicing value, for instance 0.15 cent perkw/h, which is mapped to a date and time period interval [DT1,DT2], forinstance from DT1=22:00 to DT2=22:30:00 every day.

The data concentrator receives at regular intervals, for instance every15 minutes, a utility meter message DTup_(u,c) comprising metering datameasurement DTup sent from each connected utility meter, decrypts it asrelevant, and verifies its signature. If the message is authenticated,the data concentrator derives the consumption values from the utilitymeter in the invoicing period interval [DT1, DT2] from the succession oftransmitted counter values CPT, or differential values ΔCPT, defined asmetering data measurement DTup. If the differential value ΔCPT has notyet been determined by the utility meter itself, the data concentratorderives the difference ΔCPT_(1,2) between the metering counter valueCPT2 at a given time and date DT2 and the metering counter value CPT1 ata given time and date DT1. Thus, depending on the technical nature ofthe utility meter and its predefined task, the destination dataconcentrator has to determine the differential consumption value ΔCPT onthe basis of several metering data measurements, typically at least twometering data measurements. More generally, the metering datameasurement DTup may comprise different data namely either:

at least one metering counter consumption index CPT; or

at least one metering counter consumption index CPT together with a timeand date DT information resulting from a clock readable by said utilitymeter and corresponding to the moment where the counter consumptionindex has been measured; or

directly the metering counter differential consumption value ΔCPT, e.g.if the utility meter is able to perform such a computation task.

In one embodiment, the data concentrator C then transmits the calculateddifference ΔCPT_(1,2) to the utility provider P associated with theutility meter U. Thus, at each time a difference ΔCPT has beendetermined for a time period interval ΔDT ([DT2−DT1]), this value ΔCPTis sent from the destination data concentrator to the proper utilitymanagement center, i.e. the utility management center associated to theutility meter from which comes the metering data measurement DTup. Inanother embodiment, the data concentrator C collects and calculates fora utility meter, a sequence (i.e a plurality) of values ΔCPT_(1,2),ΔCPT_(2,3), ΔCPT_(3,4) for a given reporting period of time ΔRT([RTa,RTb]), for instance one day, one week or one month, and recordsthem into a memory of the data concentrator, e.g. under a utility meterconsumption invoicing report MRup_(u,c,p). After the end of thereporting period of time RTb, the data concentrator C in the proposeddistributed computing system establishes secure communications with theutility provider P associated with each utility meter U and transmitsthe collected consumption values ΔCPT to the utility provider P, e.g. bysending the utility meter consumption invoicing report MRup_(u,c,p). Theadvantage of this solution is that the utility provider only needs toprocess one utility meter consumption invoicing report messageMRup_(u,c,p) for each reporting period of time, regardless of the actualfine gain granularity of the utility meter consumption reporting andregardless of the actual tariff updates during this period.

In order to identify their source and their destination in an opencommunication network, the utility meter consumption invoicing reportmessage MRup_(u,c,p) also includes the source utility meter identifierUid. Preferably, it further includes the destination data concentratoridentifier DCid and the utility provider identifier Pid. Theseidentifiers may be an integral value uniquely associated with theequipment at manufacturing time, a network address identifier, or anycombination thereof.

In order to ensure the integrity of the utility meter consumptioninvoicing report message MRup_(u,c,p), it can be signed so that theutility provider authenticates that the metering report comes from agenuine data concentrator source. In order to ensure the confidentialityof the utility meter consumption as desired (for instance to ensure enduser privacy), the utility meter consumption invoicing report messageMRup_(u,c,p) can also be encrypted so that the utility meter data isonly accessible by the authorized utility provider.

In a further embodiment, the data concentrator C collects andcalculates, for a plurality of utility meters which are all associatedwith a single utility management center (e.g. for each utility meter U1,U3 associated with utility provider P2), a sequence of values ΔCPT_U1_(1,2), ΔCPT_U3 _(1,2), ΔCPT_U1 _(2,3), ΔCPT_U3 _(2,3), ΔCPT_U1 _(3,4),ΔCPT_U3 _(3,4) for a given reporting period of time [RT1,RT2] (e.g. oneday, one week or one month) and records them, together with the utilitymeter identifier Uid to which each of these value refers, into a memoryof the data concentrator, e.g. under a consolidated utility meterconsumption invoicing report CR_(c,p). After the end of the reportingperiod of time RT2, the data concentrator C in the proposed distributedcomputing system establishes secure communications with the utilityprovider P3 associated with the subset of utility meters U1, U3 andtransmits the consolidated utility meter consumption invoicing reportCR_(c,p) to the utility provider P3. The advantage of this solution isthat the utility provider only needs to process one consolidatedconsumption invoicing report message CR_(c,p) for each data concentratorinstead of each utility meter, for each period of time. Accordingly, thecommunications are optimized while saving bandwidth and computingresources.

In order to identify their source and their destination in an opencommunication network, the consolidated consumption invoicing reportmessage CR_(c,p) also includes a list of the source utility metersidentifiers Uid, the destination data concentrator identifier DCid, andthe utility provider identifier Pid. These identifiers may be anintegral value uniquely associated with the equipment at manufacturingtime, a network address identifier, or any combination thereof.

In order to ensure the integrity of the consolidated consumptioninvoicing report message CR_(c,p), it can be signed so that the utilityprovider authenticates that the metering report comes from a genuinedata concentrator source. In order to ensure the confidentiality of theutility meters consumption as desired (for instance to ensure end userprivacy), the utility meter consumption invoicing report messageCR_(c,p) can also be encrypted so that the utility meters data is onlyaccessible by the authorized utility provider.

By grouping the data into one message, such as a consolidated utilitymeter consumption invoicing report, it is not possible to implement asingle cryptography system for reporting all utility meters given thatsuch a system would require a shared key for all these meters.

In the case where the network between the data concentrator and theutility meter is not reliable, it may occur that a utility meteringmessage DTup is lost. In that configuration it is preferable totransmit, as metering data measurement DTup, the counter index CPTrather than a relative differential value ΔCPT, so that the dataconcentrator can still interpolate the missing consumption value fromthe last received one and the current one and derive an acceptableconsumption invoice accordingly.

Given that providers, intermediate data concentrators C1-C4 and utilitymeters U1-U8 are interconnected between them within the communicationnetwork and given that the sender and the recipient(s) are identified inthe exchanged messages by means of identifiers Uid, DCid, Pid, thereforemessages sent to a specific recipient (e.g. a data concentrator DCid ora provider Pid) can be advantageously re-routed by an alternaterecipient to the appropriate recipient. Such a roaming can be performedby an intermediate data concentrator or by a provider that would receivea message (e.g. a utility meter message DTup_(u,c) or utility meterconsumption invoicing report message MRup_(u,c,p)), whereas it is notthe appropriate recipient of this message. Such a roaming can be appliedfor instance if the message of the sender cannot reach its recipient formany reasons, such as for temporarily maintenance reasons or failure inthe communication towards a certain recipient.

In order to simplify future updating and/or other operations directed orperformed by the utility management center such as data managementbilling, the report sent from the data concentrator to the utilitymanagement center can further comprises a detailed tariff computation,calculated on the basis of at least one tariffs table similar to thatshown in FIG. 2. Typically, such a tariffs table will be established andupdated by the utility management center but can be processed orpreprocessed by the destination data concentrator.

Alternately, the data concentrator may also send a receiptacknowledgement and/or a retransmission query to the utility meter.

The data concentrator may also further send information about the actualoffering and/or invoicing as relevant to the end user, periodically, forinstance after reporting consolidation to the utility providers.

The data concentrator may also further send a configuration message tothe utility meter to update its reporting rate.

Preferably, all of exchanged messages or reports are secured before tobe sent by means of a signature for authenticity and integrity purposesand/or by means of encryption/decryption keys. Providing securedmessages/reports involves either their encryption according to asymmetric or a private/public scheme, or the establishing of signatureenclosed to the message/report in order to ensure the authenticity andthe integrity of sending data. Secured messages/reports can also beobtained by combining signing and encryption processes.

Thus, each time messages or reports have to be exchanged, the method ofthe present invention performs a step aiming to establish a securecommunication respectively for each utility meter U1-U8 connected to thedestination data concentrator C1-C4 and for each data concentrator C1-C4connected to said utility management center P1-P3. This communicationbeing secured by signing and encrypting messages and reportsrespectively processed by the destination data concentrator C1-C4 and bythe utility management center P1-P3. Secured messages and securedreports are processed only if they are identified, on receipt, as beingauthentic by authentication means.

Accordingly, the method of the present invention could be as follows:

A method for managing utility meter communications within a networkcomprising a plurality of utility meters (U1-U8) each associated andconnected to at least one utility management center (P1-P3) through atleast one intermediate data concentrator (C1-C4), each utility meterbeing identified by a utility meter identifier Uid and being adapted toproduce and send secured utility meter messages DTup_(u,c) to adestination data concentrator identified by a data concentratoridentifier DCid, each destination data concentrator being adapted toproduce and send secured reports to said management center (P1-P3)identified by a management center identifier Pid, said method comprisingthe steps of:

preparing and sending a secured utility meter message DTup_(u,c) from autility meter (U1-U8) to said destination data concentrator (C1-C4),said utility meter message DTup_(u,c) including: a metering datameasurement DTup reported by said utility meter, said utility meteridentifier Uid, said destination data concentrator identifier DCid andsaid management center identifier Pid,

decrypting and/or verifying the authenticity and the integrity of saidsecured utility meter message DTup_(u,c) upon receipt by the destinationdata concentrator (C1-C4); in case of failure or unsuccessful result:interrupting the processing of said data concentrator message,

determining, on the basis of several metering data measurements DTup, ametering counter differential consumption value ΔCPT calculated bydifference of two metering counter consumption indexes CPT measured bysaid utility meter within a time period interval ΔDT,

preparing and sending, from the destination data concentrator towardsthe utility management center (P1-P3) to which said utility meter isassociated, a secured report containing at least said metering counterdifferential consumption value ΔCPT,

processing said report, upon receipt by the data concentrator, onlyafter having decrypted this report and/or checked its authenticity andits integrity.

The present invention also refers to a system able to implement theabove disclosed method. To this end, it suggests a system for managingutility meter communications within a network comprising a plurality ofutility meters U1-U8 each associated and connected to at least oneutility management center P1-P3 through at least one intermediate dataconcentrator C1-C4 identified as being a destination data concentratorby an identifier DCid. Each utility meters U1-U8 being identified by autility meter identifier Uid and each utility management center beingidentifier by a management center identifier Pid. This systemcomprising:

connecting means for establishing communications through communicationnetwork links Luc connecting the data concentrator to the utility metersassociated with this data concentrator, and through communicationnetwork links Lcp connecting this data concentrator to the utilitymanagement center, preferably to a plurality of utility managementcenters,

measuring means for determining a metering data measurement DTup byreading a counter consumption index CPT at each utility meter,

means, such as a message generator, for generating utility metermessages DTup_(u,c) within each utility meter U1-U8, each of theseutility meter messages comprising: the metering data measurement DTup,the utility meter identifier Uid, the destination data concentratoridentifier DCid and the management center identifier Pid,

utility meter sending means for transmitting these utility metermessages DTup_(u,c) to the destination data concentrator,

computing means for determining, on the basis of several metering datameasurements DTup, a metering counter differential consumption valueΔCPT calculated by difference of two metering counter consumptionindexes CPT measured by the utility meter within a time period intervalEDT,

data concentrator sending means for transmitting, from the destinationdata concentrator towards the utility management center P1-P3 to whichthe utility meter U1-U8 is associated, a report containing at least themetering counter differential consumption value ΔCPT, and

a central processing unit for managing all the aforementioned means.

All of the above-mentioned means can be carried out by specific modulescomprising electronic components able to achieve the functions to whicheach of those modules refer.

According to one embodiment, each utility meter of the system furthercomprises a clock readable by said measuring means for including a timeand date DT to the metering data measurement DTup.

According to another embodiment, the destination data concentrator ofthe system comprises a memory for collecting, during a reporting periodof time ΔRT, a plurality of calculated consumption values ΔCPT beforesending them to the proper utility management center, for instancewithin the report transmitted by the sending means of the dataconcentrator at the end of the reporting period of time ΔRT.

Preferably, the system of the present invention further comprisessecurity means for securing the communications exchanged, on the onehand, between the utility meters and the destination data concentratorand, on the other hand, between the latter and at least one utilitymanagement center associated with these utility meters. Securedcommunications are carried out by common means, i.e. by signatures andencryption means applied to the utility meter messages DTup_(u,c) sentby the utility meters and to the reports sent by the destination dataconcentrator. Therefore, the system is provided with means for acquiringpublic key certificates, means to authenticate these certificates, meansfor producing session key (typically random session key), means forencrypting and decrypting messages with these keys and means for sendingand receiving acknowledgment messages in case of completely successfultransmission.

1. A method for managing utility meter communications within a networkcomprising a plurality of utility meters each associated and connectedto at least one utility management center through at least oneintermediate data concentrator, each utility meter being identified by autility meter identifier and being adapted to produce and send utilitymeter messages to a destination data concentrator identified by a dataconcentrator identifier, each destination data concentrator beingadapted to produce and send reports to said management center identifiedby a management center identifier, said method comprising the steps of:sending a utility meter message from a utility meter to said destinationdata concentrator, said utility meter message including a metering datameasurement reported by said utility meter, said utility meteridentifier, said destination data concentrator identifier and saidmanagement center identifier; determining a metering counterdifferential consumption value based on a difference of two meteringcounter consumption indexes measured by said utility meter within a timeperiod interval; sending, from the destination data concentrator towardsthe utility management center to which said utility meter is associated,a report containing at least said metering counter differentialconsumption value.